I will study the ways in which electrical field stimulation (EFS) affects the transport of ions and water by the rabbit ileum. There are two lines of evidence that electrical field stimulation causes changes in ion transport: 1) EFS increases the P.D. and short circuit current of full thickness rabbit ileum mounted in a modified Ussing flux chamber, and 2) EFS causes a net secretion of Cl by enhancing the movement of Cl from the serosa to the mucosa. The neurotoxin, tetrodotoxin, prevents both the change in short circuit current and Cl movement at a concentration of 10-7M, suggesting that the effect of EFS is mediated in part by the intrinsic nerves of the intestine. In the coming months we will try to determine what neurotransmitters are responsible for the effect by using their pharmacologic antagonists, and determining the degree to which they prevent the rise in short circuit current caused by electrical field stimulation.